Sunscreen and Bug Spray: Children’s Summer Skin Care

Summer is here, and we know we’re supposed to shield children from the sun. There’s strong evidence that early sun exposure can increase children’s risk of later skin cancer, and that’s true also for darker-skinned children who are less likely to burn. Boston and Miami Beach are providing free sunscreen in public places, and now New York is talking about it, too.

Parents have certainly gotten much more aware about sun protection, though they sometimes feel a little overwhelmed by the variety of products and by the job of keeping up with the imperatives for proper use.

And with old worries about ticks and new worries about mosquito-borne viruses, parents wonder if they should also be coating a child’s exposed skin with bug repellent.

But babies’ delicate skin is more permeable than adults’, so any chemicals we apply may be more likely to be absorbed, and their immature organs may be less able to handle those chemicals. What stays on the skin may be absorbed; but what doesn’t stay on the skin doesn’t shield. Dermatological toxicology involves considering the balance between “wash in,” the risk of absorbing potentially toxic substances through the skin, and “wash out,” the loss of protection as substances are lost by sweating or water exposure or rubbing. Both are highly complex processes, with many variables, and not necessarily well studied in young children.

With little babies, the advice is always to rely on reducing exposure, on shade and clothing for sun, and on adding screens and netting to keep the bugs off. Both the Food and Drug Administration and the American Academy of Pediatrics emphasize that babies under 6 months should be kept out of direct sunlight, protected with shade, shielded with sunhats and protective clothing when they do have to be out, rather than relying on sunscreen.

Babies’ skin surface is large in proportion to their body volume and their internal fluids, putting them at high risk for heat and dehydration. So make sure they are drinking and wetting their diapers regularly.

Adults and children alike are advised to avoid the hours of maximum exposure — to stay out of the sun between 10 and 2, and to avoid going outside at dusk in areas with lots of mosquitoes. But of course, that isn’t necessarily easy.

Sun hats and protective clothing are important for older babies and toddlers, and so is avoiding those peak hours. For children under 2, “the rule of thumb in this age group is clothing first,” said Jacqueline Thomas, an assistant professor of dermatology and surgery at Nova Southeastern University in Fort Lauderdale, who is the senior author on a commentary reviewing pediatric sunscreen and sun safety guidelines published last year in the journal Clinical Pediatrics. Dark colors and more tightly woven fabrics are more effective.

As to sunscreen, experts say not to choose by what is marketed for children or babies, and to read the label carefully. In 2011, the F.D.A. required much more information to be standardized on sunscreen labels; parents should look for products with an SPF of 30 or higher, advises the American Academy of Dermatology, and make sure they are labeled as “water resistant” (lasts 40 minutes in the water) or “very water resistant” (80 minutes), and as “broad spectrum,” meaning that they block both UVA and UVB rays, both of which do damage. There is no such thing as waterproof sunscreen.

The active agents in sunscreen can be either chemical blockers or physical blockers, and the physical blockers are safer for children because they are much less likely to be absorbed. For children ages 2 to 12, look for products with titanium or zinc as their active ingredients, rather than chemical agents, which really haven’t been studied in children.

The recommended amount for an adult-size body is variously described as a shot glass and a golf ball for the trunk and extremities; for under 12, some authorities suggest using the amount that would fill a child’s cupped hand as a rough guide. It needs to be reapplied after two hours, because the efficacy is gone, even if you can still feel the lotion on your skin, and sunscreens with higher SPFs don’t last any longer than those with lower SPFs (in fact, there is no evidence that SPFs over 50 are more protective).

What about insects? Mosquito repellents generally contain either DEET, picaridin or one of several essential plant oils, most commonly oil of lemon eucalyptus, as an active ingredient; permethrin, which is meant to be applied to clothing (or sometimes already applied by manufacturers) works to repel ticks.

There has been concern in the past about DEET toxicity, and the recommendation is to avoid DEET and picaridin for babies younger than 2 months, and to avoid oil of lemon eucalyptus for children under 3 years old. But most pediatricians would recommend being very sparing with all of these substances on babies and young children, applying them only to exposed skin, right before going outside, and washing them off when you come back in. Don’t let young children apply the stuff themselves, and keep it away from their eyes and their mouths, and their hands if they tend to put those in their mouths. If possible, put the repellent on the clothing, or on the tent; there are also clip-on devices that can be attached to strollers.

Dr. Adelaide A. Hebert, a professor of dermatology and pediatrics at McGovern Medical School at the University of Texas Health Science Center at Houston, said she tends to recommend picaridin-based insect repellents such as Cutter Advanced and Off Clean Feel for children over those that contain DEET. “I like picaridin. I feel there’s less concern for parents using it with regard to toxicity,” she said. The strength of these insect repellents can vary as well, so again, it’s important to read the label. “We don’t recommend DEET strength above 20 percent because of concern about toxicity,” Dr. Hebert said.

Combination products are another problem, though the idea of a single lotion that protects against both sun and insects is very appealing. “I never recommend combination products,” said Dr. Hebert. “We don’t want to reapply the insect repellent as often as we may need to reapply the sunscreen.” Further, there’s evidence that the mixture may make the sunscreen less effective, and the chemicals more likely to be absorbed.

So keep babies out of the sun, be scrupulous about sun hats and protective clothing, about screens and mosquito netting. As children grow, don’t forget about protecting the eyes; think about broad-brimmed hats and sunglasses. If you need protection against insects, apply insect repellent over sunscreen, and reapply the sunscreen after two hours, on top of the insect repellent, which does not have to be reapplied so frequently.

The skin is the largest organ of the body, proportionally larger in the smallest children, and protecting it properly needs our care and attention.